Authorization lists should be encrypted and secured since they are so vulnerable to manipulation. Imagine if someone messed with these files without meaning to.

This may be used to explain why certain block cypher modes of operation utilise encryption alone, whereas others use encryption and decryption together:

Authorization lists should be encrypted and secured since they are so vulnerable to manipulation. What would happen if someone messed with these files by mistake?

To what end does hashing passwords in a separate file and encrypting the password file serve as security measures?

"Why are authorization lists so prone to unauthorized change that they have to be encrypted and protected against unauthorized access? What type of damage may be done if these files were updated in an unanticipated or unplanned way?

Why must authorization lists be encrypted? What happens if these files are accidentally modified?

The tripwire program is an example of a host-based intrusion detection system. This tool examines files and folders on the system and notifies the administrator of any changes. It employs a protected database of cryptographic checksums for each file reviewed and compares them as they are scanned. It must be set with a list of files and directories to check and changes allowed. It can allow adding new entries to log files but not changing old ones. What are the benefits and drawbacks of employing such a tool? Consider the issue of selecting which files should be checked and which should be reviewed rarely. Consider the time spent configuring the application and monitoring the results.

Asymmetric ciphers' unreversible operations make them more secure. This chapter covered various asymmetric operations. What asymmetric operations can you think of?